1. Field of the Invention
The present invention concerns an apparatus having a heat treatment chamber for textile threads that are continuously deposited and transported on a continuous perforated conveyor belt which is continuously driven through the chamber. The apparatus has a tubular enclosure that demarcates the treatment chamber. The apparatus is equipped with an entrance and an exit for the conveyor belt and the threads. At least one forced circulation unit provided within the treatment chamber. Furthermore, the apparatus is provided with a casing which is crossed by the conveyor belt, the casing defining a fluid treatment circuit, with treatment fluid being comprised of air and/or of steam. The circuit has at least one blower to force the treatment fluid to vertically through the conveyor belt and the threads.
2. Discussion of Background and Relevant Information
The International Patent Application published under the number W088/06653 shows, especially in FIGS. 4 and 5, such a heat treatment chamber having three forced circulation units, each of them having a casing forming a closed circuit treatment fluid. In this circuit, a blower positioned above the conveyor belt sucks in a fluid, that is comprised of hot air or a mixture of air and steam, and the blower then recycles the fluid towards the base of the casing, via a lateral conduit in (which the fluid temperature may be adjusted to a predetermined value) by injection of steam or cold air. One of the functions of these units is to create treatment conditions that vary gradually along the trajectory of the belt, according to the threads carried by the unit. Another function may consist of maintaining predetermined conditions at each point of the trajectory in case of a non-desired stop of the belt. However, in practice, the means that are provided for adjusting the temperature do not easily enable obtaining the exact temperatures and conditions that are substantially different from the forced circulation unit positioned in the same treatment chamber.